Chain wrench



Sept. 24, 1940. J THOMAS 2,215,824

CHAIN WRENCH Filed Dec. 29, 1938- 122 uezz Z01".

Patented Sept. 24, 1940 UNITED STATES PATENT v 7 2,215, 24 p CHAIN WRENCH Alfred J. Thomas, Braintree, Mass.

Application December 29, 1938, Serial No. 248,154

2 Claims.

X strength, they have been made large and cumbersome. Even when reduced in size, they are awkward and difficult to handle, since their defects are structural and inherent.

There. is therefore a considerable demand for chain wrenches that are sufficiently versatile,

that are compact and easily used, and which will meet the needs of the general public. No wrenches of this description are now available. There is no chain wrench which the ordinary public can use about the house for the multiple small needs which constantly arise. The average householder needs a chain wrench that is strong but light in weight,.one that can be used in places of limited access, one that can turn anything from a water pipe to a bottle cap, and the same Wrench that must grip a large pipe firmly must not dent or gouge more delicate objects. But in all the years that such needs have existed, no one has produced a chain wrench that could supply the demand.

I have discovered thecause ofthe inherent defects which have heretofore existed in all chain wrenches known tome, and have invented a chain wrench having a structure which is, for the first .time, free from such defects.

I have found that the above mentioned defects in the chain wrenches previously known are due to the lack of proper cooperation between the lever portion and the chain portion of the wrench in that these elements are not structurally-suited to act together efficiently. Since objects vary in size, the chain must be quite long in order that the wrench may be sufliciently versatile and adjustable. For most objects, therefore, there will be an excess length of chain. The head of the lever bar must usually grip an intermediate portion of the chain, and the manner in which the chain and lever cooperate is of considerable importance, but apparently no one has hitherto appreciated the significance of proper cooperation. Therefore, others have tended to focus their attention on the gripping head of the lever bar without realizing that their failure to consider both gripping head and chain as equally important cooperating elements has resulted in modifications of the Wrench which lessen its utility.

My improved chain wrench, in one suitable form, has a thin lever bar provided at one end with an integral, knurled hook which hooks into 5 thespaces of a chain made of spaced parallel links joined by spaced parallel pins. Each spaced cylindrical pin may thus be engaged by the hook, and the excess chain doubled back,

with the result that the hook, while engaging one pin, occupiestwoof said spaces. It therefore follows that no part of the entire wrench is wider than the chain, an accomplishment of considerable importance when the utility of the wrench is considered. It often happens that very little space is allowed for the introduction and application of a wrench. In such places, it is often very difficult if not impossible to use any of the chain wrenches now known, such as those having a yoke-shaped head for gripping the chain, or those in which the chainmust pass through some enlarged portion of the wrench, or those inwhich any portion of the complete wrench must be wider than the operative part of the chain in order that the wrench operate as intended.

The knurled hook above mentioned is at the extreme end of the lever bar and forms an integral part thereof. This hook also serves to grip the object, thus resulting in a firm hold on sequently tend to slip, or, if tightened, to mar or dent the object to which they are applied. Such wrenches have had toothed lever bars which bear inwardly with great. pressure, or othermeans of gripping in which the force is likewise directed toward the interior of the object. The grip of the knurled hook of my invention, while ensuring a firm hold on the object, acts with a force that is directed almost at a tangent to the surface of the object, rather than with a crushing force directed into it.

The invention will be best understood from the following description in conjunction with the accompanying drawing. It is to be understood that the invention is not limited to the details of construction and arrangement of parts. illustrated in the drawing, since the invention as defined by the claims hereinafter appended, may be otherwise embodied without departure from the spirit and scope thereof.

It is also to be understood that the terms here. used are for the purpose of description and illustration and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

In the accompanying drawing,

Fig. 1 is a View in side elevation of my improved chain wrench.

Fig. 2 is likewise a view in side elevation showing the wrench in engagement with a pipe.

Fig. 3 is a View in elevation of an edge of the wrench showing said Wrench in engagement with a pipe.

In the drawing, a lever bar I has at one end thereof an integrally formed hook 2 the outer edge of which is provided with knurls 3. A chain 4 is made up of two parallel rows of links, an inner pair of links 5 and an outer pair of links 5a all joined by parallel pins 6. The chain 4 is pivotally connected to a portion of the lever l adjacent the hook 2 by a pin 1 which passes through the last pair of links 5 of the chain 4 and through thelever bar I. The space between the inner pairs of links 5 must be sufficient to allow a hook of reasonable strength to enter, but in other respects the distance between the links and the size of the chain 4 are determined by the strength desired, and the use for which thewrench is designed. Where the wrench is to be used in narrowplaces, the chain 4 should be as fine as is compatible with the strength necessary to perform the work intended. A powerful wrench for use in narrow places can be made with a chain in which the distance between the links 5 is not over one-quarter of an inch. The length of the links and consequent spacing of the pins 6 are subject to the same qualifications. Once such length and the spacing of the pins are determined, however, they should be reasonablyuniform throughout the length of the chain, since the hook 2 in engaging one of the pins 6, will pass through two spaces in the chain,

as shown in Fig. 2.

The lateral thickness of the hook 2 is determined by the same considerations. It must be thick enough toperform the work intended, but must be small enough to pass through the spaces between the inner links 5. The longitudinal thickness of the hook 2 must not be wider than the distancebetween the pins 6. The head end of the lever bar (i. e., near the hook) should be of the same thickness as the hook 2, and the greater portion of said lever bar should not be thicker than the width of the chain 4. While a small portion of the handle end or said lever bar may be enlarged beyond these limits, such enlargement must not interfere with the requirement that the head end of said bar and a considerable portion of the lever bar adjacent thereto must not be wider than the chain, in order that the wrench may be used in confined places. I prefer to have both the hook 2 and the lever bar I of uniform thickness throughout.

In applicants wrench, the hook 2 may be described as having a face or tip portion and a back or heel portion. The distance from face to heel is the length, the distance from the slot edge to the object engaging surface may be termed the width, and the distance from one side of the hook to the other, the thickness, which is the same as that of the bar I. The face and heel portions of the hook have the same width and the same thickness.

In operation, the chain 4 is passed about the object to be turned, such as the pipe 8, the excess length of chain is doubled back and the hook 2 is passed through the two endmost spaces of said chain and about the exposed pin 6. The lever bar I is then moved in the direction of the excess chain, thereby forcing the knurls 3 of the hook 2 to grasp the object and pulling taut the heel end of the chain 4. Continued movement causes the object to rotate.

Having described my invention, what I claim is:

1. A chain wrench having, in combination, a. lever bar, a hook of uniform width from face portion to heel portion integrally formed on one extreme end of the lever bar, and a chain pivotally connected to said lever bar at a point near said hook substantially equidistant from all parts of the object engaging surface of said hook and extending from that edge of the lever bar on which the face of the hook is formed, said chain comprising a series of sections of spaced parallel links pivotally connected by pins to enable each of said sections to fold against the preceding section to expose a connecting pin to said hook.-

2. A chain wrench having, in combination, a lever bar, a knurled hook of uniform width and thickness from face portion to heel portion integrally formed on one extreme end of the lever bar, and a chain pivotally connected to said lever bar at a point near said hook substantially equidistant from both the face end and the heel end of said hook and extending from that edge of the lever bar on which the face ofthe hook is formed, said chain comprising a series of sections of spaced parallel links pivotally connected by pins to enable each of said sections to fold against the preceding section to expose a connecting pin to said hook.

ALFRED J. THOMAS. 

